Display screen or portion thereof having a graphical user interface



The FIGURE is a front view of a display screen or portion thereof having a graphical user interface.

The dot-dashed broken lines depict a boundary of the display screen or portion thereof or a boundary on the display screen and form no part of the claimed design. The dashed broken lines depict portions of the display screen or portion thereof having a graphical user interface which form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof having a graphical user interface, as shown and described. 